http断点续传简单实现（java)

/* :
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**SiteFileFetch.java SR%h=`t  
*/ s=~r. x  
package NetFox; 1 W2AE?  
import java.io.*; m]=|%a6  
import java.net.*; &Dqg<U  
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public class SiteFileFetch extends Thread { n:`> QY  
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SiteInfoBean siteInfoBean = null; //文件信息Bean "%<Oadz ap  
long[] nStartPos; //开始位置 +MGEO+  
long[] nEndPos; //结束位置 -2K`:}\y&  
FileSplitterFetch[] fileSplitterFetch; //子线程对象 h/V0}|b  
long nFileLength; //文件长度 /=lrdp!a  
boolean bFirst = true; //是否第一次取文件 +x-n,!(  
boolean bStop = false; //停止标志 53=s'DZ  
File tmpFile; //文件下载的临时信息 Uj0DX>I  
DataOutputStream output; //输出到文件的输出流 i~n>dc YW  
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//负责整个文件的抓取，控制内部线程（FileSplitterFetch类） t{Q9Kv  
public SiteFileFetch(SiteInfoBean bean) throws IOException #J, `a.  
{ 6@ET3v  
siteInfoBean = bean; ]5YG*sD4  
//tmpFile = File.createTempFile ("zhong","1111",new File(bean.getSFilePath())); KF
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tmpFile = new File(bean.getSFilePath()+File.separator + bean.getSFileName()+".info"); [jeZZB  
if(tmpFile.exists ()) }Wn6r_:  
{ [FAoC3 k-h  
bFirst = false; +*DXzVC  
read_nPos(); B+*F?k[  
} CcLP/  
else EbY%:jR  
{ mUm9[X~'  
nStartPos = new long[bean.getNSplitter()]; ,N<xyx.  
nEndPos = new long[bean.getNSplitter()]; ^E{~{  
} ;I:jd")  
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} 0{@E=}}h  
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public void run() qI) Yzc/  
{ v5;c}n  
//获得文件长度 ,-vbR&  
//分割文件 bv4lgRE6Y  
//实例FileSplitterFetch 0V}%'Ec<e  
//启动FileSplitterFetch线程 /$%apci8  
//等待子线程返回 <Ktx*(D  
try{ R8W{[@  
if(bFirst) ?r'rvu'/  
{ 0%cbno@1V  
nFileLength = getFileSize(); V'mQ{[{R  
if(nFileLength == -1) t1 OnA#]/_  
{ TF^Rh4  
System.err.println("File Length is not known!"); &+xNR2";  
} 4Bd[r7  
else if(nFileLength == -2) Kaa
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{ 8)\ ?6C  
System.err.println("File is not access!"); /Pxt f~$  
} 4@.qM6 \\q  
else ?N~rms e  
{ xeIt7b?#  
for(int i=0;i<nStartPos.length;i++) y['$^T?
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{ 'hf#Q9W5  
nStartPos = (long)(i*(nFileLength/nStartPos.length)); \@N8[  
} q$yTG!q*  
for(int i=0;i<nEndPos.length-1;i++) sPyq.oG  
{ G yvEc3|@  
nEndPos = nStartPos[i+1]; p[!&D}&6h  
} %|I~8>m  
nEndPos[nEndPos.length-1] = nFileLength; YiTiJ9jf  
} ^|5vmI'E  
} [O2xE037h`  
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//启动子线程 >OgA3)X  
fileSplitterFetch = new FileSplitterFetch[nStartPos.length]; c/jU+,_g  
for(int i=0;i<nStartPos.length;i++)
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{ N<zD<q  
fileSplitterFetch = new FileSplitterFetch(siteInfoBean.getSSiteURL(), .D(H@3qA@  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(), @>}!g9c  
nStartPos,nEndPos,i); Rp^kD ,*  
Utility.log("Thread " + i + " , nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); 8doKB<#_+=  
fileSplitterFetch.start(); 7v]>ID  
} )>QpR8 G-  
// fileSplitterFetch[nPos.length-1] = new FileSplitterFetch(siteInfoBean.getSSiteURL(), V`fp%7W  
siteInfoBean.getSFilePath() + File.separator + siteInfoBean.getSFileName(),nPos[nPos.length-1],nFileLength,nPos.length-1); c$Z3P%aP'V  
// Utility.log("Thread " + (nPos.length-1) + " , nStartPos = " + nPos[nPos.length-1] + ", z\]]d?d?;  
nEndPos = " + nFileLength); DI{VJ&n66  
// fileSplitterFetch[nPos.length-1].start(); W4%I%&j  
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bBk_2lg=4)  
//等待子线程结束 v-B{7 ~=#Z  
//int count = 0; $Ypt /`  
//是否结束while循环 l+HmG< P  
boolean breakWhile = false; E#[_"^n  
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while(!bStop) ]$oo1ssZ1  
{ o,>9|EMQZ  
write_nPos(); ++w7jVi9  
Utility.sleep(500); HL]8E}e\"  
breakWhile = true; Lp.dF)C\  
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for(int i=0;i<nStartPos.length;i++) BpBMFEiP  
{ C jISU$O  
if(!fileSplitterFetch.bDownOver) mhV
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{ |(u6xPs;P  
breakWhile = false; \5M1;  
break; \NU^Jc_k7  
} (yA`h@@WS  
} @rI+.X  
if(breakWhile) bWWZGl9  
break; O$zXDxn  
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//count++; KG<. s<  
//if(count>4) N!!=9'fGF  
// siteStop(); 7IkNS  
} ) rw!. )  
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System.err.println("文件下载结束！"); ~/^q>z!\4  
} ^x2zMB\t  
catch(Exception e){e.printStackTrace ();} hhWIwR  
} @=rYOQj|  
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//获得文件长度 ?, B4  
public long getFileSize() JOwm|%>3a  
{ Fi)(~ji:  
int nFileLength = -1; \.ukZqB3 0  
try{ .ni<'  
URL url = new URL(siteInfoBean.getSSiteURL()); M`V<`  
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();
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httpConnection.setRequestProperty("User-Agent","NetFox"); O]_a$U*6  
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int responseCode=httpConnection.getResponseCode(); ]QC9y:3  
if(responseCode>=400) .>#X*u  
{ y'L7o V?L9  
processErrorCode(responseCode); q7z`oK5  
return -2; //-2 represent access is error Ls<^z@I  
} {ooztC  
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String sHeader; moS0y?N  
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for(int i=1;;i++) (^
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{ iX%9$Bft<  
//DataInputStream in = new DataInputStream(httpConnection.getInputStream ()); ~Y/:]&wF  
//Utility.log(in.readLine()); hKnAWKb0  
sHeader=httpConnection.getHeaderFieldKey(i); =j~BAS*"  
if(sHeader!=null) t =V| '  
{ w)N~u%  
if(sHeader.equals("Content-Length")) gFpub_  
{ Gr-~&pm  
nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader)); ]
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break; wKU9I[]  
} R_^0Un([  
} 3D;?X@  
else 1-V"uLy@gC  
break; "7q!u,u  
} }1 ,\*)5  
} UpaF>,kM  
catch(IOException e){e.printStackTrace ();} ?wP/l  
catch(Exception e){e.printStackTrace ();} `=V p 0tPI  
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Utility.log(nFileLength); o_8Wnx^  
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return nFileLength; 6(=B`Z}a  
} !\VzX  
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//保存下载信息（文件指针位置） B"YN+S
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private void write_nPos() 9(3]t}J5 d  
{ xkCM*5:  
try{ 0qINa:Ori  
output = new DataOutputStream(new FileOutputStream(tmpFile)); IwXWtVL  
output.writeInt(nStartPos.length); > ^=n|%  
for(int i=0;i<nStartPos.length;i++) X1HEeJ|  
{ -Ew>3Q  
// output.writeLong(nPos); C7O
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output.writeLong(fileSplitterFetch.nStartPos); Lk)I;;  
output.writeLong(fileSplitterFetch.nEndPos); I cASzSjYX  
} :i4AkBNK  
output.close(); E{0e5.{  
} 5dGfO:Dy_  
catch(IOException e){e.printStackTrace ();} NH;e|8  
catch(Exception e){e.printStackTrace ();} 0W0GSDx  
} )DmydyQ'  
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//读取保存的下载信息（文件指针位置） iX o(  
private void read_nPos() _Pno9|  
{ @F]w]d  
try{ XV/7K"  
DataInputStream input = new DataInputStream(new FileInputStream(tmpFile)); E[WU  
int nCount = input.readInt(); ht*N[Pi4;  
nStartPos = new long[nCount]; A!,c@Kv 3  
nEndPos = new long[nCount]; 0BNH~,0u  
for(int i=0;i<nStartPos.length;i++) Tw djBMte  
{ ny{S&f  
nStartPos = input.readLong(); Ni8%K6]z  
nEndPos = input.readLong(); 
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} B{b?j*fHJ  
input.close(); {+zG.1o^  
} O1UArD  
catch(IOException e){e.printStackTrace ();} \6
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catch(Exception e){e.printStackTrace ();} sj4\lpZ3h  
} \pk9i+t  
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private void processErrorCode(int nErrorCode) m62Zta  
{ 9 Jw,ls  
System.err.println("Error Code : " + nErrorCode); ]isq}Qv~  
} 9% C]s  
/Yb8= eM  
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//停止文件下载 HU'w[r6a  
public void siteStop() [ :)
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{ TE;f*!  
bStop = true; u(FOSmNkN  
for(int i=0;i<nStartPos.length;i++) %X's/;(Lx`  
fileSplitterFetch.splitterStop(); ]h
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}
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} [0qswsV  
//负责部分文件的抓取 +_/ys!  
**FileSplitterFetch.java w,X)g{^T  
*/ )Nqx=ms[(!  
package NetFox; \#JX
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import java.io.*; !?_CIt$p  
import java.net.*; ?FNgJx*\S  
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public class FileSplitterFetch extends Thread { `k>C%6FG$#  
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String sURL; //File URL +'SL5d*  
long nStartPos; //File Snippet Start Position P5h
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long nEndPos; //File Snippet End Position -<k)|]8  
int nThreadID; //Thread's ID k~so+k&=b  
boolean bDownOver = false; //Downing is over EcX7wrl9x  
boolean bStop = false; //Stop identical Go1xyd:k  
FileAccessI fileAccessI = null; //File Access interface y\j[\UZKO  
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public FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException QVRQUd  
{ Xp|4WM  
this.sURL = sURL; P=1Ku|k  
this.nStartPos = nStart; kP}l"CN4  
this.nEndPos = nEnd; {ZSAPq4)L  
nThreadID = id; tV_3!7m0$  
fileAccessI = new FileAccessI(sName,nStartPos);//定位 7XT(n v  
} E.;Hm;  
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public void run() ygV_"=+|N  
{ WV'u}-v^  
while(nStartPos < nEndPos && !bStop) jl}!UG  
{
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try{ @`+\v
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URL url = new URL(sURL); [kpQ:'P3
 
HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection (); *~4<CP+"0  
httpConnection.setRequestProperty("User-Agent","NetFox"); c%O97J.5b  
String sProperty = "bytes="+nStartPos+"-"; @YRy)+  
httpConnection.setRequestProperty("RANGE",sProperty); KPDJ$,
:  
Utility.log(sProperty); w8~R=k  
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InputStream input = httpConnection.getInputStream(); w2
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//logResponseHead(httpConnection); <,it<$f#  
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byte[] b = new byte[1024]; Yc?S<  
int nRead; Mv/ SU">F  
while((nRead=input.read(b,0,1024)) > 0 && nStartPos < nEndPos && !bStop) %scIZCrI~  
{ ]l h=ZC  
nStartPos += fileAccessI.write(b,0,nRead); qc.TYp  
//if(nThreadID == 1) (e~9T MY  
// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); Ac{TqiIv  
} ;qy;;usa  
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Utility.log("Thread " + nThreadID + " is over!"); G5OGyQp  
bDownOver = true; Im-qGB0C  
//nPos = fileAccessI.write (b,0,nRead); _a9oHg  
} O(-6Zqk8Q  
catch(Exception e){e.printStackTrace ();} b@=H$"  
} t~dK\>L  
} b?cO+PY01  
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hP{+`\&<f  
//打印回应的头信息 6C"zBJcGc  
public void logResponseHead(HttpURLConnection con) ,Xn%0]  
{ a
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for(int i=1;;i++) !mWm@}Ujg  
{ 9bRUN<  
String header=con.getHeaderFieldKey(i); \(=xc2  
if(header!=null) |7n%8JsY!"  
//responseHeaders.put(header,httpConnection.getHeaderField(header)); p:$v,3:  
Utility.log(header+" : "+con.getHeaderField(header)); A /c  
else 7!(/7U6rP  
break; 3?`TEw~'  
} :/6aBM?  
} 8 l= EL7  
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public void splitterStop() })kx#_o]'d  
{ GV) "[O  
bStop = true; )+Z.J]$O-  
} @c"s6h&  
{*g{9`   
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} @].!}tz  
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/* Uc,

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**FileAccess.java FqGMHM\J  
*//文件访问(定位，写) ~#VDJ[Z  
package NetFox; B<Cg_C  
import java.io.*; Y`$\o  
#u+qV!4  
x./"SQ=R+  
public class FileAccessI implements Serializable{ b KIL@AI  
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//RandomAccessFile类用于在任意一个文件的特定位置上读/写字节 vg@5`U`^h  
RandomAccessFile oSavedFile; GcA|JS=>  
long nPos; ?dv-`)S&  
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public FileAccessI() throws IOException /zQx}U)TP  
{ cBOK@\x:Wi  
this("",0); c=?6`m,"M  
} ?UIW&*h}  
8'qlg|{!~  
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public FileAccessI(String sName,long nPos) throws IOException /[/{m]  
{ .!lLj1?p  
oSavedFile = new RandomAccessFile(sName,"rw"); 1=9GV+`n  
this.nPos = nPos; CK|AXz+EN  
oSavedFile.seek(nPos); cH:&S=>h  
} -`z%<)!Y  
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public synchronized int write(byte[] b,int nStart,int nLen) x;} 25A|  
{ o /1+ }f  
int n = -1;
& @_
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try{ `)KGajB  
oSavedFile.write(b,nStart,nLen); ?|}qT05  
n = nLen; (]&B'1b  
} 3,*A VcQA  
catch(IOException e) :f_oN3F p  
{ :9x]5;ma  
e.printStackTrace (); |f1^&97=+  
} c(b`eUOO  
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return n; L*4=b (3  
} y@2"[fo3~  
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} Lc]hwMGR*  
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/* JX&%5sn(  
**SiteInfoBean.java ;Oq>c=9%  
*/ 3A~<|<}t  
package NetFox; 1;{nU.If  
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public class SiteInfoBean { ux6)K= ]  
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private String sSiteURL; //Site's URL P
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private String sFilePath; //Saved File's Path k.)YFKi  
private String sFileName; //Saved File's Name $$Ibr]$5  
private int nSplitter; //Count of Splited Downloading File 0a@tPskV  
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public SiteInfoBean() IkA~+6UY  
{//nSplitter的缺省值为5 d>#X+;-k  
//default value of nSplitter is 5 u%1JdEWZd  
this("","","",5); OS>%pgv  
} o"P)(;  
IeA/<'Us  
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public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) Hl{ul'o  
{ X2,v'`U5&  
sSiteURL= sURL; <Zf
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sFilePath = sPath; OH]45bd &7  
sFileName = sName; QC]<`!  
this.nSplitter = nSpiltter; w_~tY*IwB  
!B9Yw/Ba  
\FCPD.2s+  
}
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~%
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public String getSSiteURL() [{&OcEf  
{ ajM\\a?  
return sSiteURL; 9j-;-`$S  
} qAlX#]  
d}Y#l}!E6  
<RH%FhT  
public void setSSiteURL(String value) 6-5{7E}/b  
{ b%C7 kL-  
sSiteURL = value; qkC{IBN92  
} P~x4h{~Gd  
x1Gc|K/-  
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public String getSFilePath() g@?R"  
{ &=T>($3r94  
return sFilePath; c3<H272\  
} X%;4G^%ZI  
v=
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public void setSFilePath(String value) OP_\V8=  
{ o(D_ /]'8  
sFilePath = value; Pe11azJ  
} {D,- Whi  
W~l.feW$i  
jsKKg^g  
public String getSFileName() *8u<?~9F  
{ 6vU%Y_n=y]  
return sFileName; N!\1O,  
} z$/s` |]  
J~ *>pp#U  
{8%KO1xB  
public void setSFileName(String value) `Uvc^  
{ G \$x.  
sFileName = value; %_>8.7  
} <p`
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U:PtRSdn!b  
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public int getNSplitter()  2q9$5   
{ NKVLd_f k  
return nSplitter; aHitPPlq  
} nVP|
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9sv#TT5V  
.i#'IS0c  
public void setNSplitter(int nCount) UZ:z|a3  
{ 01]W@\(  
nSplitter = nCount; 1@~ 1vsJ  
} I-Hg6WtB  
} %qVD-Jln  
p<FqK/  
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/* ZlcEeG  
**Utility.java 7$R^u7DZ  
*/ ,~Lx7 5{  
package NetFox; /(%!txSNEt  
UdpuQzV<4`  
'Awd:Aed5  
public class Utility { QUz4 Kt  
ArT@BqWd  
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public Utility() $KoGh_h  
{ g/w<T+v  
4i"fHVp8  
=&: |a$C  
} B,ao%3t  
%w/vKB"nO  
//线程睡眠 +7y#c20  
public static void sleep(int nSecond) L/N%ft]!T  
{ y (%y'xBP  
try{ &}#zG5eu  
Thread.sleep(nSecond); 1T4#+kW&  
} ?ihRt+eR~  
catch(Exception e) M~.1:%khM  
{ J)H*tzg  
e.printStackTrace (); -O $!sFmY  
} gBXoEn]
 
} p@d_Ru  
]#'&x%m  
//日志 z)u\(W*\iA  
public static void log(String sMsg) xd+aO=)Td  
{ Xhpcu1nA  
System.err.println(sMsg); 8 9maN  
} ]r\!Z <<(  
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"9NWsy}<c  
public static void log(int sMsg) {=MRJg!U  
{ \[AJWyP  
System.err.println(sMsg); X7*fmD=Uy  
} xi)$t#K"  
} 1q|iw  
J(9{P/  
79+i4(H  
/* Ir Y\Q)  
**TestMethod.java ]i>,oxBWe  
*/ }LoMS<O-[  
package NetFox; Qs<L$"L1  
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public class TestMethod {
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5?f!hB|6  
public TestMethod() \GZ|fmYn  
{ ///xx/weblogic60b2_win.exe nL]eGC  
try{ R.YUUXT  
SiteInfoBean bean = new SiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_win.exe",5); O;0VKNn['  
//SiteInfoBean bean = new SiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5); D&OskM60  
SiteFileFetch fileFetch = new SiteFileFetch(bean); y-~_W 6\  
fileFetch.start(); w,OPM}) il  
}
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catch(Exception e){e.printStackTrace ();} _SMi`ie#  
<00=bZzX  
tHr4/  
} ` ^;J<l  
#S[Y}-]T  
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public static void main(String[] args) )&%Y{a#  
{ ?[)V  
new TestMethod(); p!\GJ a",  
} .Y^pDR12  
} %Nx,ZD@  
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